This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We have demonstrated excellent results in diagnosing normal, two types of benign lesions and malignant lesions on freshly excised tissue using Raman spectroscopy. The study thus supported moving the technique to a clinical setting for further testing of its efficacy in breast cancer diagnosis. As a result, we pursued clinical study. We collected data in the University Hospitals of Cleveland pathology suite, typically within half an hour of excision during partial and whole mastectomy. The main goals of this study was to validate our in vitro diagnostic algorithm on a large data set which closely mimics an in vivo environment and to elucidate differences between the Raman spectra of fresh-frozen and fresh breast tissues. Another clinical study is scheduled. The main goal of this study is expanding our diagnostic algorithm to include pathologies not seen previously in our studies, such as ductal carcinoma in situ and microcalcifications.